1. Field of the Invention
The present invention relates to a differential output circuit that outputs differential signals.
2. Description of Related Art
As the resolution of an image is increased, devices, such as camera sensors, plasma display panels, and liquid crystal displays, need to transmit large amounts of data at a high speed. In order to transmit a large amount of data at a high speed, a high-speed signal transmission system using small-amplitude signals is required. In a differential small-amplitude interface standard, such as an LVDS (low voltage differential signal) standard or a CML (current mode logic) standard, used instead of a CMOS interface, for example, timing or noise problems have been solved, and there is an attempt to reduce power consumption. In addition, the differential small-amplitude interface standards, such as an RSDS (reduced swing differential signaling) standard, a mini-LVDS standard, and a subLVDS standard, have been used.
The above-mentioned various standards are used for the purpose of signal transmission, and different interface circuits are used according to the standards. The interfaces are the same except for the structure of a receiving end or the electrical characteristics of an output signal, and it is possible to change the structure of an output circuit to correspond to a plurality of different standards.
International Publication No. WO2005/043769 discloses a structure in which a plurality of output circuits corresponding to a plurality of different standards are provided, the outputs of the output circuits are connected to each other, and the output circuits are switched according to the standard used. However, the structure having a plurality of output circuits corresponding to a plurality of different standards has problems such as when a chip area is increased, a leakage current is increased.